Brian MacKenzie said:*Hi Dave,
Could you please explain this part further, or point me to somewhere
if it is already documented?
Is the option available for a Schlumpf hub (and would the schlumpf
frame be required) in a stockton build? *
Hmmm... it's not yet documented anywhere, really, Brian. The concept
is this:
There are two sets of identical gears in the drive train. This
constraint allows the chains to be of the same length, which greatly
simplifies design and reliability. One set of the gears is fixed
(welded in), while the other set is changeable (bolted in).
Those two sets of gears have different ranges. One set, the welded set,
ranges from about 12 teeth to about 22 teeth, in steps of one. The
other set, the variable set, ranges from about 20 teeth to about 26
teeth, in steps of two, for a total of 4 different sizes.
The welded set is essentially integral to the wheel. That may change,
but for now that is the case. So the customer/rider chooses the number
of teeth for that set upon purchase, based upon his/her application.
The second set is the changeable set. Probably additional gears and
chains will be an optional kit so people don't have to buy a huge number
of gears all at once.
A typical set might be 20 teeth on the fixed set, and 20-26 teeth on the
changeable set. For a 29er with a 30" wheel diameter, that choice gives
gear-inch numbers (effective wheel diameters) of 30" (1.00),
36.3"(1.21), 43.2"(1.44) and 50.7" (1.69). For a cadence of 100 cps,
that results in speeds of 8.9 mph, 10.8 mph, 12.9 mph, and 15.1 mph. So
overall, the range is 30"- 51" for that setup.
Since the fixed set is available in steps of one from 22 teeth to 12
teeth, one can finely tune the range from (24.8" - 41.9"😉 to (83.3" -
140.8"😉. Every range has four steps in it, corresponding to the 4
changeable gear sizes. We move the range up and down by selecting the
fixed set.
This approach makes the best possible use of commercially available
parts and limits the need for parts that are specially-constructed for
this unicycle.
I have a spreadsheet that you can look at, but it is not yet ready for
public use, especially posting on the Internet. For most people, it
would raise more questions than it would answer (in its present
configuration), and confuse the issues.
The actual ranges may differ slightly from this, but the above numbers
should be close.
As for LiveWire using a Schlumpf hub... certainly I hope to be able to
do that in the future. My current belief is that the hub is too narrow
for the 36" wheel, and marginal for 29", especially for brake use. I
understand that the company may widen the hub in the future, and I look
forward to that change.
--
U-Turn - Cool water for the flame
Weep in the dojo... laugh on the battlefield.
'LiveWire Unicycles' (http://www.livewireunicycles.com)
'Strongest Coker Wheel in the World'
(http://www.unicyclist.com/gallery/albup39)
'29er Tire Study' (http://u-turn.unicyclist.com/29erTireStudy/)
'New York Unicycle Club' (http://www.newyorkunicycle.com)
-- Dave Stockton
------------------------------------------------------------------------
U-Turn's Profile: http://www.unicyclist.com/profile/691
View this thread: http://www.unicyclist.com/thread/42861
